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| author | Abel Vesa <abelvesa@linux.com> | 2017-04-03 23:58:54 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@armlinux.org.uk> | 2017-04-20 11:19:43 +0100 |
| commit | 6f05d0761af612e04572ba4d65b4c0274a88444f (patch) | |
| tree | 2171d2bc5260bd2444d82214f7cdf5c1ecb1eb01 | |
| parent | b089c31c519c3906c14801b6ec483e18a5152a50 (diff) | |
| download | linux-6f05d0761af612e04572ba4d65b4c0274a88444f.tar.gz linux-6f05d0761af612e04572ba4d65b4c0274a88444f.tar.bz2 linux-6f05d0761af612e04572ba4d65b4c0274a88444f.zip | |
ARM: 8668/1: ftrace: Fix dynamic ftrace with DEBUG_RODATA and !FRAME_POINTER
The support for dynamic ftrace with CONFIG_DEBUG_RODATA involves
overriding the weak arch_ftrace_update_code() with a variant which makes
the kernel text writable around the patching.
This override was however added under the CONFIG_OLD_MCOUNT ifdef, and
CONFIG_OLD_MCOUNT is only enabled if frame pointers are enabled.
This leads to non-functional dynamic ftrace (ftrace triggers a
WARN_ON()) when CONFIG_DEBUG_RODATA is enabled and CONFIG_FRAME_POINTER
is not.
Move the override out of that ifdef and into the CONFIG_DYNAMIC_FTRACE
ifdef where it belongs.
Fixes: 80d6b0c2eed2a ("ARM: mm: allow text and rodata sections to be read-only")
Suggested-by: Nicolai Stange <nicstange@gmail.com>
Suggested-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Abel Vesa <abelvesa@gmail.com>
Acked-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
| -rw-r--r-- | arch/arm/kernel/ftrace.c | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/arch/arm/kernel/ftrace.c b/arch/arm/kernel/ftrace.c index 3f1759411d51..414e60ed0257 100644 --- a/arch/arm/kernel/ftrace.c +++ b/arch/arm/kernel/ftrace.c @@ -29,11 +29,6 @@ #endif #ifdef CONFIG_DYNAMIC_FTRACE -#ifdef CONFIG_OLD_MCOUNT -#define OLD_MCOUNT_ADDR ((unsigned long) mcount) -#define OLD_FTRACE_ADDR ((unsigned long) ftrace_caller_old) - -#define OLD_NOP 0xe1a00000 /* mov r0, r0 */ static int __ftrace_modify_code(void *data) { @@ -51,6 +46,12 @@ void arch_ftrace_update_code(int command) stop_machine(__ftrace_modify_code, &command, NULL); } +#ifdef CONFIG_OLD_MCOUNT +#define OLD_MCOUNT_ADDR ((unsigned long) mcount) +#define OLD_FTRACE_ADDR ((unsigned long) ftrace_caller_old) + +#define OLD_NOP 0xe1a00000 /* mov r0, r0 */ + static unsigned long ftrace_nop_replace(struct dyn_ftrace *rec) { return rec->arch.old_mcount ? OLD_NOP : NOP; |